Colloquium Abstract - Plotkin - 2025Oct24

October 24, 2025

11:00am Mountain

Richard Plotkin (University of Nevada, Reno)

 

The Radio Signatures of Low-Mass Active Galactic Nuclei

 

Abstract

The supermassive black holes (M > 10^6 Msun) that occupy the centers of large galaxies today must have been born with lower masses and grown through accretion and/or mergers. We are now in an exciting era where lower mass black holes (10^4 - 10^6 Msun), which I will refer to as “low-mass active galactic nuclei (AGNs)”, are being identified at the centers of some low-mass galaxies. These low-mass AGNs provide opportunities to study objects that may be analogous to the (intermediary) building blocks of supermassive black holes. In this talk, I will present the radio properties of low-mass AGNs, based on a sample of objects selected through optical and X-ray emission, and then followed-up with the Karl G. Jansky Very Large Array. I will then discuss results illustrating how synchrotron radio jets evolve with accretion rate, and also how joint radio and X-ray considerations allow us to diagnose rapid super-Eddington accretion in a subset of objects. The latter has implications for understanding accretion-growth channels of supermassive black holes in the early Universe. In addition to improved physical insight into accretion and jet physics in this new mass regime, these results will inform future techniques for using radio observations to assemble purer samples of low-mass AGNs, including with facilities like a next generation Very Large Array..


Local Host: Amy Kimball

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